Fuel supply systems of said type are often used in modern-day motor vehicles and are known from practice. The suction jet pump is arranged in a return line leading from the internal combustion engine into the fuel tank or is supplied by the fuel pump with fuel as a propellant. The valve of the known fuel supply system ensures that the suction jet pump has a sufficient delivery capacity even in the case of a low propulsion quantity of fuel. Since the propulsion pressure of fuel can be subject to intense fluctuations, the valve is preloaded by a spring force into a closed position. With increasing pressure, the valve is opened and the suction jet pump obtains fuel as propellant. With increasing pressure, the opening of the valve increases, as a result of which the delivery capacity of the suction jet pump increases.
A disadvantage of the known fuel supply system is that, in the case of a variable propulsion pressure, the delivery capacity of the suction jet pump varies. At a high propulsion pressure, the propulsion quantity is therefore too high. This however results in a loss of hydraulic power.